Research and clinical observation have shown that depression is associated with a negative bias in memory and attention. For both drug and psychological treatments, it is important to clarify the neural mechanisms of this bias. We propose to examine elementary processes of orienting and attention that are disordered in depression, and that can be related to specific neural systems. In addition, we examine the influence of depressed affect on spatial and object memory with paradigms that can be analyzed on the basis of primate studies and studies of human amnesia. A five year series of experiments manipulates the motivational influences on these paradigms with normal subjects, then extends the most informative experiments to depressed students and to community subjects meeting criteria for Major Depressive Episode and Dysthymia. For both the attention and the memory paradigms, we implement new methods of characterizing brain electrical activity with dense scalp electrode arrays. These methods hold the promise of visualizing brain activity with a temporal resolution suited to the dynamic psychological operations of corticolimbic networks.